Automatic fire extinguishing device



Feb. 14, 1950 E.'G.'ASHCRAFT AUTOMATIC FIRE EXTINGUISl- IING DEVICEFiled Nov. 29, 1944 Patented Feb. 14, 1950 AUTOMATIC FIRE EXTINGUISHINGDEVICE Ernest G. Ashcraft, Chicago, Ill., assignor to Iva CoryneDavidson, Hollywood, Calif.

Application November 29, 1944, Serial No. 565,658

13 Claims.

This invention relates to improvements in fire extinguishing devicesemploying a new principle of atomizing and vaporizing a suitable liquidfor the purpose of instantaneously forming a thick and heavy layer of afire extinguishing gas.

The principal object of the invention is to provide a novel device andmethod for automatically detecting and smothering the fire when it firststarts, and for preventing its continuance by surrounding the point ofignition and adjacent areas with a blanket of fire extinguishing agentin its most efficient gaseous form.

Experience and common knowledge shows that many liquid chemicalextinguishing agents such as carbon tetrachloride depend for their fireextinguishing action upon sufficient vaporization to surround andexclude oxygen from the blazing material. Such agents have no more thanthe ordinary cooling efiect of water when they are applied to the blazein liquid form.

In carrying out my invention, I provide an improved form of containerfor a liquid fire extinguishing agent such as carbon tetrachloride,especially adapted to be installed as independent units or fixtures toprotect predetermined areas, and having means for automaticallyreleasing the liquid in an atomized form in such quantities as to form ablanket of gas for excluding oxygen from the blaze.

The invention may best be understood by reference to the accompanyingdrawing, in which:

Figure 1 is a view in vertical section showing a fire extinguishingdevice constructed in accordance with my invention.

Figure 2 is a detail section of the heat-sensitive unit employed forautomatically releasing the liquid from the device.

Figure 3 is a section taken on line 3-3 of Figure 1.

Referring now to details of the embodiment of my invention illustratedin the drawing, in indicates a hollow metal containing vessel, hereinspheroidal in shape, having a canopy H at its upper end adapted to fitagainst the ceiling of a room so that the body of the container issuspended above the area to be protected. The container has a dischargevalve fitting indicated generally at l2 at its bottom consisting of avalve member I 3 fitting against a tapered opening in a valve seat I5.Said valve fitting has a plurality of small apertures 16, I 6, leadinginto the tapered opening in the valve seat so as to permit escape ofliquid in a finely atomized spray when the valve member i3 is opened bymovement away from said valve seat,

2 The movement of the valve member I3 is controlled through a rod I1extending upwardly axially of the container and suitably connected to abellows member l8, as by nuts I9 threaded on the upper end of said rod.

The bellows l8 extends upwardly in a cylindrical casing fittingin thetop wall 2| of the container. In the form shown herein, the casing 20has a flared shoulder 20a which is secured to said containerwall as bywelding, and also has a reduced tubular extension 22 extendingdownwardly and rigidly connected at its lower end to the discharge valvefitting H. The valve rod I! is movable in, and spaced from the sidewalls of the tubular extension 22, as shown. The casing 20 with itstubular extension 22 therefore forms, in effect, a through-bolt forreenforcing the walls of the container, and maintaining the operatingparts of the valve and its control mechanism in proper spaced relation.1

The upper end of the bellows [8 has an outwardly extending flange 23,sealed against a shoulder 24in the widened upper end of casing 20 as bya spacing ring 25 held in place by a cap 26 shown herein, the said bodyis made in upper and lower half-sections, joined together as by weldingto a horizontally disposed, flanged ring 3! on the interior of saidcontainer body.

The arrangement of parts so far described is such that a quantity offire extinguishing fluid such as carbon tetrachloride may be put intothe container body so as to partially fill the latter and be placedunder pressure by air or other suitable gas, pumped into said containerabove the level of the liquid, as indicated in Figure 1 of the drawings.Pressure may be applied through a check valve 32 herein shown as mountedon the side wall of the casing 20 outside of the-bellows I8. I

The pressure in the container communicates freely through the apertures30, 3-0 in the lower end of casing 20, and is exerted against thebellows 18 so as to force the latter upwardly against the compression ofspring 29, thus closing the valve member l3. It will be understood thatthe efiectlve area of the bellows I8 is substantially greater than theeifective area of the valve member l3 and that the pressure in the spacewithin and above the bellows H3 in casing 28 is initially at atmosphericpressure, when pressure is applied to the interior of the container.

Referring now to the means for automatically releasing the liquid when afire occurs, tubes 34, 35, are connected to a heat-responsive deviceindicated generally at 36. One tube 34 communicates through port 31 incap 26 with the exterior surface of the bellows l8, while the other tube35 communicates with the interior of the container body l through port38 in one side of casing 20 below the bellows. The arrangement is such,that when open communication between the tubes 34 and 35 is established,the pressure within the container body below the bellows 18 becomesequalized with that effective on the top of the bellows, so as torelease the discharge valve under compression of said bellows and thespring 29.

Details of the heat-responsive device 36 are shown in Figure 2. Saiddevice consists of a C-shaped clamp 40 having a pair of opposedadjusting screws 4|, 4| in the jaws thereof which engage similarcircular end plates 42, 42. Each of said end plates has a centrallydisposed boss 44 with a port 45 therein opening toward the center of theend plate and communicating with one of the tubes 34 or 35 leading tothe extinguisher unit. An enlarged metal disc 4'! is mounted between theopposed end plates 42, 42. Said disc has a centrally disposed aperture48 which is closed by a fusible plug 49 which normally forms afluid-tight barrier to seal off communication between the tubes 34 and35. Heat insulating washers t, 50 are interposed between each end plate42 and the adjacent surface of the disc 4'! to provide a fluid-tightjoint when the end plates are clamped against the disc by the screws 4|,4!.

The fusible plug 49 may be of any suitable material capable of becomingmelted when heated to a relatively low temperature. For instance, saidplug may be made of Woods metal, which fuses at approximately 165 F. Inthe form shown said plug is retained in the aperture 48 of the disc 41by providing said aperture with V-shaped side walls and pressing orexpanding the plug securely within said aperture to form a fluid-tightseal. The disc 4'! is preferably made of copper or similar heatconducting metal and is tapered toward its edges so as to afford amaximum heat conduction surface and a least heat absorptive mass, forthe conducting the heat of the surrounding air quickly to the fusibleplug. The heat insulating washers 50, 5!! resist dissipation of heat tothe end plates 42, 42.

The heat-responsive device 36 may be located at any suitable pointadjacent to or remote from the container body I0 where it will give themost efficient action, depending upon the conditions and nature of theinstallation. In the form shown in Figure 1 the heat-responsive deviceis mounted immediately adjacent the canopy l I so as to be near theceiling where rising heat from an incipient fire will effect a promptactuation of the device. The tubes 34, 35 can also be extended asdesired so as to dispose the heatresponsive device 36 to a point nearerto where a blaze is likely to be started. The container in may besecured to the ceiling or other support by any suitable means. In theform shown the canopy II is provided with a plurality of 4 screws aroundits flanged margin which can be screwed into such support.

The use and operation of the automatic extinguishing device abovedescribed will now be readily understood as follows:

A quantity of liquid fire extinguishing agent, of which carbontetrachloride is a good example, is placed in the container body l0under pressure. The container may be made of sufficient size to hold twoor three quarts of such liquid when about half full, leaving a spaceabove the liquid level for the introduction of air or gas under pressureso as to fully charge the container and compress the bellows 28 tomaintain the discharge valve H5 in closed position. It would beunderstood that when air pressure is applied to the interior of thecontainer the fusible plug 49 in the heat-responsive device 3i; willform a barrier between the exterior and interior surfaces of the bellows28 so that said bellows will be compressed against atmospheric pressureabove the bellows and in the upper end of the casing 29 and the tube 34leading to one side of said fusible plug, and the coil spring 29 willalso be compressed. The arrangement is such that the increased pressurewithin the container body is sufiicient to maintain the discharge valve$3 in closed position indefinitely, until the fusible plug 49 inaperture 48 becomes melted under fire conditions. Thereuponcommunication is im mediately established between the exterior andinterior surfaces of the bellows, so as to counterbalance the pressureon opposite sides of the latter, and permit the valve member l3 to beopened by expansion of the bellows and the coil spring 29. Opening ofthe discharge valve will cause the fire extinguishing liquid to bedischarged under pressure through the small discharge orifices I6, IS inthe tapered valve seat l4, and at the same time gas under pressure isdischarged from above the liquid level through apertures 39, 30 incasing 20 and between the rod l1 and the surrounding walls of thetubular extension 22 so as to mix with and atomize the liquid as it isdischarged from the tapered valve seat 14. Thus, the liquid will beatomized immediately in fine particles and spread laterally over a widearea below the extinguishing device.

The ratio of extinguisher liquid discharged through apertures l6, l6 andthe amount of gas discharged through the extension tube 22 may bedetermined by experiment to produce the desired atomizing effect,depending upon the nature of the extinguishing fluid, the gas pressure,and the relative volume of liquid and gas employed in the container.This ratio may be controlled by various means, as for instance, byproviding an optimum ratio between the total area of the holes 30, 30 incasing 20 and the discharge orifices l6, IS in the valve member l2.

It will be understood further that special advantages are attained byutilizing afire extinguishing agent which vaporizes readily atapproximately the same, or slightly below the melting point of thefusible plug 49 used in the heatresponsive device 36. For instance,where carbon tetrachloride is employed (which vaporizes at about 165 F.)the fusible plug made of Woods metal is designed to melt at 165 F.Consequently, when the heat of the surrounding air has been raised by anincipient fire to the point where the heat-responsive device isactuated, and the liquid is discharged in atomized form from thecontainer, the temperature will be suflicient to vaporize the dischargedfluid immediately upon Memes contact with the heated air, so as to forma blanket of gas, heavier than air, which will descend at once andenvelope the blaze and surrounding area so as to exclude oxygen from theblaze and put out the fire.

My improved form of extinguishing device is particularly effective whena plurality of them are disposed at pro-determined spaced intervals ofroom or building areas to be protected from fire, so that each deviceserves a pre-determined area. My improved device is, therefore, suitablefor replacing more expensive and complicated Water sprinkler systems andhas the additional advantages of providing a fire extinguishing agentwhich is usually much more efiicient than water, and does not cause somuch damage to a wide variety of goods and furnishings. My improved formof extinguisher is also more efficient than portable extinguishers of'the type commonly used inasmuch as it is always ready for automaticaction within its prescribed area, and does not depend upon the humanelement for its proper effectiveness.

Although I have suggested the use of carbon tetrachloride as a preferredfire extinguishing agent, it will be readily understood that otherchemicals having fire extinguishing characteristics can be employed ifdesired. In fact, water can likewise be used to give comparativelylimited and yet effective results, where the use of chemicals may beprohibitive.

As an additional safety feature for my improved fire-extinguishingdevice, an electricv alarm circuit of any suitable'form may be employedin conjunction therewith to give an automatic signal when the deviceoperates to release its charge either due to fire or by accident. In theform shown herein the valve control rod I! is extended into the cap 26at the upper end of the casing in position to engage contacts 55 and 56in said cap which herein is made of a suitable non-conducting material.The contacts 55 and 56 are bridged by rod I! as long as the device is infully charged condition, soas to keep a relay 57, disposed at someremote point, energized. When the rod I1 is moved to Open the atomizernozzle, however, the relay will be de-energized to cause a suitableelectric signal 59 to be operated in the usual manner.

Although I have shown and described a certain embodiment of myinvention, it will'be understood that I do not wish to be limited to theexact construction shown and described, but that various' changes andmodifications may be made without departing from the spirit and scope ofthe invention as defined in the appended claims.

I claim:

1. In a fire-extinguishing device, a container for holding a quantity ofliquid fire-extinguishing agent, and a gas under pressure, an atomizingdischarge nozzle communicating with said container, a valve meansresponsive to the pressure in said container for closing said nozzle,and means responsive to predetermined temperature conditions forrendering said pressure-responsive means inoperative so as to cause said.valve to open and discharge the liquid through said atomizing nozzleunder pressure of the gas in said container.

2. In a fire-extinguishing device comprising a closed container forholding a quantity of liquid fire-extinguishing agent, and a gas underpressure, atomizing nozzle means for said container having a fluiddischarge orifice communicating with the latter near its bottom, and agas discharge orifice communicating with said container near its top,valve means responsive to the pressure in said container for closingsaid nozzle means, and means responsive to predetermined temperatureconditions for renderingsaid pressure-responsive valve-closing meansinoperative so as to cause a mixture of liquid and gas to be releasedthrough said nozzle under pressure of said gas.

3. In a fire-extinguishing device, a container for holding a quantity ofliquid fire-extinguishing agent, and a gas under pressure above saidliquid, an atomizing nozzle having a liquid discharge outletcommunicating directly with the bottom of said containenand a conduitleading from said nozzle to a point above the normal liquid level insaid container, a pressure-responsive diaphragm communicating with theinterior of said container, valve means connected with said diaphragmarranged to close said liquid discharge outlet and conduit under apredetermined pressure in said container, and other conduit means foreffecting communication between opposite sides of said diaphragm underpredetermined, temperature conditionsso as to permit said valve means toopen under the pressure in said container.

4. In a fire-extinguishing device, a container for holding a quantity ofliquid fire-extinguishing agent, and a gas under pressure above saidliquid, said container having a discharge nozzle at its lower end, apressure-responsive diaphragm having communication at its inner sidewith the interior of said container, a valve for said nozzle havingoperating connection with said. diaphragm but said diaphragm having agreater efiective area than that of said valve so as to close saidnozzle under predetermined pressure conditions in said container, andpressure conducting means affording connection between the interior ofsaid container and the outer side of said diaphragm normally having aheat-responsive barrier therein, and operative upon disrupting of saidbarrier to equalize the pressure on opposite sides of said diaphragm,and thereby permit said valve to open under the'pressure in saidcontainer.

'5. In a fire-extinguishing device, a container for holding a quantityof liquid fire-extinguishing agent, and a gas under pressure above saidliquid, said container havinga discharge nozzle at its lower end, aconduit leading from said nozzle to the upper part of said container, apressure-responsive diaphragm having communication at one side with theinterior of said container, a valve for said nozzle having operatingconnection with said diaphragm through said conduit, said diaphragmhaving a greater efiective area than that of said valve so as to closesaid nozzle under predetermined pressure conditions in said container,and pressure conducting means affording connection between the interiorof said container and the exterior of said diaphragm normally having aheat-responsive barrier therein, and operative upon disrupting of saidbarrier to counteract the pressure on the interior of said diaphragm,and thereby permit said valve means to open said nozzle under thepressure in said container.

6. In a fire-extinguisher or the like, a closed container, a hollowtubular member rigidly connecting opposite walls of said container, saidtubular member having an enlarged portion at one end,pressure-responsive diaphragm means in said enlarged portion, dischargevalve means for said container mounted on the opposite end of saidtubular member, and means operatively connecting said valve means withsaid diaphragm means, extending through said tubular member.

'7.'In a fire-extinguisher or the like, a closed con ainer, a hollowtubular member rigidly conne ing opposite walls of said container, saidtubular member having an enlarged portion at one end having detachableclosure means accessible from the exterior of said container, pressureresponsive diaphragm means in said enlarged portion, discharge valvemeans for said container mounted on the opposite end of said tubularmember, and means operatively connecting said valve means with saiddiaphragm means, extending through said tubular member.

8. In a fire-extinguisher or the like, a closed container for holding aquantity of liquid and a gas above said liquid under pressure foratomizing said liquid, a hollow tubular member rig-idly connectingopposed upper and lower walls of said container, an atomizing nozzle forsaid con tainer mounted on the lower end of said tubular member havingliquid discharge outlet means communicating with the lower portion ofsaid container, valve means in said nozzle, valve control means at theupper end of said tubular member connected to said valve by a rodextending through said tubular member, said tubular member also havinggas discharge outlet means disposed adjacent to upper end thereof abovethe normal liquid level in said container.

9. In a heat-responsive control device, the combination of a pair ofopposed end members having aligned ducts therein, a barrier memberdisposed between said end members and having an aperture therethroughregistering with said ducts, said barrier member including a metal plateextending radially beyond said end members and having a plug in saidaperture fusible under, predetermined temperature conditions forpermitting communication between said ducts.

10. In a heat-responsive control device, the combination of a pair ofopposed end members having aligned ducts therein, a barrier memberdisposed between said end members and having an aperture therethroughregistering with said ducts, said barrier member including a metal,

plate extending radially beyond said end members and tapered toward itsmargins, said barrier member also having a plug in said aperture fusibleunder predetermined temperature conditions for permitting communicationbetween said ducts.

11. In a heat-responsive control device, the combination of a pair ofopposed end members having aligned fluid ducts therein, a barrier memberdisposed between said end members and having an aperture therethroughregistering, with said ducts, said barrier member including a metalplate extending radially beyond said end members, said barrier memberhaving a plug in said aperture fusible under predetermined temperatureconditions for permitting communication between said ducts, and heatinsulating washers interposed between said metal plate and each of saidend members.

12. In a heat-responsive control device, the combination of a pair ofopposed end members having aligned fluid ducts therein, a barrier memberdisposed between said end members and having an aperture therethroughregistering with said ducts, said barrier member including a metal plateextending radially beyond said end members, and having a plug in saidaperture fusible under predetermined temperature conditions forpermitting communication between said ducts, and means for clamping saidend members together to retain said barrier member in placetherebetween.

13. In a fire extinguisher, a casing containing a body offire-extinguishing liquid and a gas under pressure positionedthereabove, a valve positioned in said casing below the liquid leveltherein and through which said liquid can be expelled by the expansionof said gas, and means to open said valve, said means including: apressure-operated bellows in said casing exposed exteriorly to thecollapsing force of said gas under pressure, a spring tending to expandsaid bellows against said pressure, a conduit interiorly connecting saidbellows to said gas under pressure, and a fusible disc normally closingsaid conduit and adapted to melt in the presence of a predeterminedtemperature to open said conduit to enable gas under pressure'to balancesaid collapsing force and permit said spring to expand said bellows toopen said valve.

- ERNEST G; ASI-ICRAFT.

REFERENCES CITED -The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

